What is a 24-hour blood pressure monitor test? 

If you are thought to have high or low blood pressure or have symptoms of fainting, your doctor may request that you have this test. The test measures your blood pressure at different times over a 24-hour period. 

An inflatable cuff is secured around your upper arm and connected to a small monitoring device worn around your waist. The cuff will inflate and deflate at regular intervals over a 24-hour period to measure and record your blood pressure. You do not need to stay in hospital and you can continue with your normal daily activities during the test.

Why do I need a 24-hour blood pressure monitor test?

It is normal for blood pressure to change during the day because of anxiety, diet, exercise, sleep or any blood pressure medication you may take. As a result, taking a single blood pressure measurement in the clinic is not always a very accurate way of checking your blood pressure.

The test will give your doctor more detailed information about your blood pressure during your daily life.

How is the monitor fitted?

It is a good idea to wear a loose-fitting top or shirt to your appointment as this makes it easier to fit the monitor. A cardiac physiologist will fit the inflatable cuff on the arm of your choice. It should sit comfortably around your arm so please reposition it if needed. If the cuff moves during the monitoring period, the results may not be accurate. The cuff is connected to a small monitor, which you will wear around your waist clipped into a belt or waistband. It takes about 10 minutes to fit the cuff and monitor.


You will be asked to return the monitor to the non-invasive cardiology department. Ideally, the department would prefer for the monitor to be returned in person the following day. We can give you a pre-paid first-class envelope to return the monitor so please ask at the fitting if this is what you would prefer.

Please make sure you follow the department’s instructions about returning your monitor as other patients may have their BP monitor appointment cancelled if you do not return the monitor on time.

The non-invasive cardiology team aims to produce a report within 24 hours. All results are uploaded to the electronic patient record system so that your doctor can look at the results immediately.

Contact our cardiac physiologists

Royal Brompton Hospital 020 7351 8641

Harefield Hospital  01895 828 566

Fainting happens when your blood pressure drops (hypotension). At this time, your heart rate may also drop or even pause for a few seconds.

Download the patient information leaflet:

24-hour blood pressure monitor test - Harefield Hospital - Dec 2016 (PDF, 348KB)